UAV for Landmine Detection Using SDR-Based GPR Technology

This chapter presents an approach for explosive-landmine detection on-board an autonomous aerial drone. The chapter describes the design, implementation and integration of a ground penetrating radar (GPR) using a software defined radio (SDR) platform into the aerial drone. The chapter?s goal is first to tackle in detail the development of a custom-designed lightweight GPR by approaching interplay between hardware and software radio on an SDR platform. The SDR-based GPR system results on a much lighter sensing device compared against the conventional GPR systems found in the literature and with the capability of re-configuration in real-time for different landmines and terrains, with the capability of detecting landmines under terrains with different dielectric characteristics. Secondly, the chapter introduce the integration of the SDR-based GPR into an autonomous drone by describing the mechanical integration, communication system, the graphical user interface (GUI) together with the landmine detection and geo-mapping. This chapter approach completely the hardware and software implementation topics of the on-board GPR system given first a comprehensive background of the software-defined radar technology and second presenting the main features of the Tx and Rx modules. Additional details are presented related with the mechanical and functional integration of the GPR into the UAV system

SENSING SMALL CHANGES IN A WAVE CHAOTIC SCATTERING SYSTEM AND ENHANCING WAVE FOCUSING USING TIME REVERSAL MIRRORS

Wave-based motion sensors, such as radar and sonar, are designed to detect objects within a direct line-of-sight of the sensor. As a result, surveillance of a cavity with multiple internal partitions generally demands use of a network of sensors. In the first part of the dissertation, we propose and test a new paradigm of sensing that can work in such cavities using a single sensor. The sensor utilizes the time reversal invariance and spatial reciprocity properties of the wave equation, and the ray chaotic nature of most real world cavities. Specifically, classical analogs of the quantum fidelity and the Loschmidt echo are developed. The sensor was used to detect perturbations to local boundary conditions of an acoustic cavity, and the medium of wave propagation. This result opens up various real world sensing applications in which a false negative cannot be tolerated. The sensor is also shown to quantitatively measure perturbations that change the volume of a wave chaotic cavity while leaving its shape intact. Volume changes that are as small as 54 parts in a million were measured using microwaves with 5cm wavelength inside a one cubic meter wave chaotic cavity. These results open up interesting applications such as monitoring the spatial uniformity of the temperature of a homogeneous cavity during heating up / cooling down procedures, etc. The second part of the dissertation is dedicated to improving the performance of time reversal (TR) mirrors, which suffer from dissipation. TR mirrors can, under ideal circumstances, precisely reconstruct a wave disturbance which happened at an earlier time, at any given later time. TR mirrors have found applications in imaging, communication, targeted energy focusing, sensing, etc. Two techniques are proposed and tested to overcome the effects of dissipation on TR mirrors. First, a tunable iterative technique is used to improve the temporal focusing of a TR mirror. Second, the technique of exponential amplification is proposed to overcome the effect of dissipation on TR mirrors. The applicability of these techniques is tested experimentally using an electromagnetic TR mirror, and numerically using a model of the star graph

GPR applications across Engineering and Geosciences disciplines in Italy: a review

In this paper, a review of the main ground-penetrating radar (GPR) applications, technologies, and methodologies used in Italy is given. The discussion has been organized in accordance with the field of application, and the use of this technology has been contextualized with cultural and territorial peculiarities, as well as with social, economic, and infrastructure requirements, which make the Italian territory a comprehensive large-scale study case to analyze. First, an overview on the use of GPR worldwide compared to its usage in Italy over the history is provided. Subsequently, the state of the art about the main GPR activities in Italy is deepened and divided according to the field of application. Notwithstanding a slight delay in delivering recognized literature studies with respect to other forefront countries, it has been shown how the Italian contribution is now aligned with the highest world standards of research and innovation in the field of GPR. Finally, possible research perspectives on the usage of GPR in Italy are briefly discussed

Journal of Telecommunications and Information Technology, 2017, nr 3

kwartalni

Differential ultra-wideband microwave imaging: principle application challenges

Wideband microwave imaging is of interest wherever optical opaque scenarios need to be analyzed, as these waves can penetrate biological tissues, many building materials, or industrial materials. One of the challenges of microwave imaging is the computation of the image from the measurement data because of the need to solve extensive inverse scattering problems due to the sometimes complicated wave propagation. The inversion problem simplifies if only spatially limited objects—point objects, in the simplest case—with temporally variable scattering properties are of interest. Differential imaging uses this time variance by observing the scenario under test over a certain time interval. Such problems exist in medical diagnostics, in the search for surviving earthquake victims, monitoring of the vitality of persons, detection of wood pests, control of industrial processes, and much more. This paper gives an overview of imaging methods for point-like targets and discusses the impact of target variations onto the radar data. Because the target variations are very weak in many applications, a major issue of differential imaging concerns the suppression of random effects by appropriate data processing and concepts of radar hardware. The paper introduces related methods and approaches, and some applications illustrate their performance

A Survey of multimedia streaming in wireless sensor networks: progress, issues and design challenges

Advancements in Complementary Metal Oxide Semiconductor (CMOS) technology have enabled Wireless Sensor Networks (WSN) to gather, process and transport multimedia (MM) data as well and not just limited to handling ordinary scalar data anymore. This new generation of WSN type is called Wireless Multimedia Sensor Networks (WMSNs). Better and yet relatively cheaper sensors that are able to sense both scalar data and multimedia data with more advanced functionalities such as being able to handle rather intense computations easily have sprung up. In this paper, the applications, architectures, challenges and issues faced in the design of WMSNs are explored. Security and privacy issues, over all requirements, proposed and implemented solutions so far, some of the successful achievements and other related works in the field are also highlighted. Open research areas are pointed out and a few solution suggestions to the still persistent problems are made, which, to the best of my knowledge, so far have not been explored yet

Millimetre-Resolution Photonics-Assisted Radar

Radar is essential in applications such as anti-collision systems for driving, airport security screening, and contactless vital sign detection. The demand for high-resolution and real-time recognition in radar applications is growing, driving the development of electronic radars with increased bandwidth, higher frequency, and improved reconfigurability. However, conventional electronic approaches are challenging due to limitations in synthesising radar signals, limiting performance. In contrast, microwave photonics-enabled radars have gained interest because they offer numerous benefits compared to traditional electronic methods. Photonics-assisted techniques provide a broad fractional bandwidth at the optical carrier frequency and enable spectrum manipulation, producing wideband and high-resolution radar signals in various formats. However, photonic-based methods face limitations like low time-frequency linearity due to the inherent nonlinearity of lasers, restricted RF bandwidth, limited stability of the photonic frequency multipliers, and difficulties in achieving extended sensing with dispersion-based techniques. In response to these challenges, this thesis presents approaches for generating broadband radar signals with high time-frequency linearity using recirculated unidirectional optical frequency-shifted modulation. The photonics-assisted system allows flexible bandwidth tuning from sub-GHz to over 30 GHz and requires only MHz-level electronics. Such a system offers millimetre-level range resolution and a high imaging refresh rate, detecting fast-moving objects using the ISAR technique. With millimetre-level resolution and micrometre accuracy, this system supports contactless vital sign detection, capturing precise respiratory patterns from simulators and a living body using a cane toad. In the end, we highlight the promise of merging radar and LiDAR, foreshadowing future advancements in sensor fusion for enhanced sensing performance and resilience